Emergency extension mechanism



y 9 a'. H. oowTv- 6 EMERGENCY. EXTENSION MECHANISM Original Filed Oct. 12, 1936 2 Sheets-Sheet l July 29, 1947. ow- 2,424,926

EMERGENCY. EXTENSION MECHANISM Original Filed Oct. 12, 1936 2 Sheets-Sheet 2 Patented July 29, 1947 2,424,926 we EMERGENCY EXTENSION MECHANISM George HerbertDowty, Cheltenham, England Original application October 12, 1936, Serial No. 105,337; Divided and this application July 2, 1942, Serial No. 449,501

This invention relates to an improved emergency extension mechanism for quickly extending an aircraft undercarriage upon the failure of the normal means of extension therefor.

This application is a division of my copending application, Serial No. 105,337, filed October 12, 1936, which application resulted in Patent No. 2,288,968, dated July 7, 1942. v

One of the principal objects of the invention is to provide an emergency extension mechanism which will, by a single jerk by the'pilot upon a strap or cable, release a source of stored, resilient energy for immediately extending an aircraft undercarriage.

Another object of the invention is to provide an emergency extension mechanism which will, after release, require no further attentionupon the part of the pilot.

A further object of the invention is to provide mechanism of this characterwhich will be of relatively simple construction and which will be positive in operation.

Still another object of the invention is to pro- Vide an emergency extension mechanism which will in no way interfere with the normal means of extension and retraction of the undercarriage.

Further objects of the invention will become apparent during the course of the following description.

In the drawings:

Figure 1 is a perspective view showing my improved emergency extension mechanism as it would appear installed upon an aircraft, the normal means of extension being shown schematically in dotted lines.

Figure 2 is an enlarged detail side elevation of my improved emergency extension mechanism as it would appear with the undercarriage in retracted position, the position of the mechanism when the undercarriage is extended being shown in dotted lines, and i'.

Figure 3 is an enlarged detail sectional view showing the structure of the cylinder.

A conventional undercarriage is shown at l and comprises a wheel carrying leg structure la which is pivotally connected, for rearward and upward swinging movement, to a point on the aircraft at 2, the aircraft being shown generally at 2a. Pivotally connected to the leg structure at 3 is a knuckle-jointed or articulated radius rod 3 which comprises a lower part 4 and an upper part 5 which are interconnected by an axle 6, the upper part 5 having its upper end pivotally connected to a portion of the aircraft 2 at T. The pivot pins 2 and I are, of course, fixed points in the aircraft.

4'Claims. (01144-102) In Figure 2 the undercarriage is shown in full lines retracted and in broken lines as it would appear in extended position. At the pivot point 3 there is attached one end of a cable 8 which is led over a pulley or fairlead 9 which is carried coaxially with the axle 6, and then over a pulley or fairlead II] which is rotatably mounted within the aircraft 72 and thence into a cylinder H which is fixedly mounted in the aircraft. As best seen in Figure 3, the inner, or upper, end of the cable 8 is disposed within the cylinder H and has mounted thereona collar 12 which defines a stop, and an eye 13 in which engages the lower end of a relatively light tension spring it, which spring is contained within the cylinder and has its opposite end anchored at l5 in an extension l5 of said cylinder ll.

Mounted in the cylinder 1 l at the opposite end thereof from the spring '84, is a relatively strong compression spring l6 which is compressed between a plug "i at the lower end of the cylinder, and atapered conical locking member I1 which normally bears against the lower surface of the collar or stop l2. As will be observed, the upper end of the cable 8 extends axially through the plug l6? through the coiled spring is and through the locking member I! and the collar [2, said cable being anchored against displacement by a washer l'l which is disposed adjacent the eye I3.

' Formed in the wall of the cylinder, substantially medially of its length, is a circumferentially disposed series of openings, and normally disposed in the openings is a series of locking balls l8. The locking balls I8 are normally held midway'of the openings and against the tapered portion of the locking member I! by the inner faceio-f a release element I!) which is slidable on the outer surface of the cylinder. The release element l9, as best seen in Figure 2, includes a uide sleeve l9 which is slidable on a guide rod 20, said guide rod being disposed in parallel spaced relation to the cylinder and extending throughout the entire length of said cylinder and being held in spaced relation by brackets 20 The sleeve 20 is formed with a yoke 20* and pivotally connected with said yoke is the lower end of av releasing cable 21-. Formed in the release element l9 near one end is a circumferentially extending trough 22 which communicates with the inner face of the element and is of a size sufficient to accommodate the balls It.

At 22, in Figures 1 and 2, I have shown conventional mechanism for extending and retracting the undercarriage. This mechanism includes a cylinder 22 which is fed with fluid from a source of hydraulic pressure through pipes 22 feature of the'sinvention when :it-is remembered that .ja .pilot; depending upon .thelnormal'imeans of extensionior his undercarriage, waits until and 22 The mechanism also includes a piston of stored, resilient energy, means operatively rod M which has its lower end connected with connecting the source of energy with the underthe lower part 4 of the articulated radius rod 3. car iage, and means for releasing said source Under normal conditions, when fluid is fed of energy for extending th undercarriage upon through the pipe 22 to the cylind r 2 the h 5 failure of the conventional means of extension, 13011 in the y der Will be advanced for urgm said last mentioned means including a cable for the piston rod 22 downwardlyvfor extending the gpgratiOll bythepilot.

undercarriage in the normal manner.- Under 2.1m combination with a retractable underthese conditions, the spring M will "take up any c rriage fer aircraft, and conventional means slack in the cable 8. 9- completely operative in itself for extending the In e event that the mechanism Should undercarriage, a completely independent underfail to function, for any reason,:1'rt;is-'only rneces; 5 marriage, extending means, including a cylinder sary for the pilot to give the releasing cable. 2' containing ,asource of energy, means operatively 5131111 jerk- When this t 'P connecting the source of energy in the cylinder element I9 will be shifted-upwardly n :15iflwithithezundercarriage and means connected with cylmder N 1111111 the trough *con'fmntsfthef ltheecylinder and shiftable by a single movement openings in said cylinder. When this position is ,i lrelasingthe source of energy for emergency reached by the element I9, the member l1 will, extension of the undercarriage pressure of the S g earn e balls-lflinto "3, In combination with a retractable undersald camnmlg balls the carriagefor aircraft, and. conventional means r g m) 9 u -5e completelypperative in itself for extending the to shdewlthmthe Y d fp l eew e d undercafriagega completely independent emermember the spr'mg Wm urgetheimemher genoy extension mechanism for quickly extendalong the cylinder and'against the tension of the relatively-light spring M, 'Thecoll'ar l 2will also 2 beshifted and as aresult the cable 8 will be pulled :upwardly within the cylinder for i extendingthe undercarriage -from-the position stiown in full lines in Figure 2 to that shown in" broken lines. 7 i

It should be understood thatthe :shape of th'e cylinder ll and thapartioular arrangement of the locking means may be varied considerably without departing from thespiritof the invention. It should alsobe understood'that,:although Ihave shown the cylinder l l "as b'eing mounted directly above the undercarriage,'.said cylinder may be remotely mounted if so desired.

It is desired particularly to call attention to the iact that butonemovement on'th'epart-of the 340 pilot is needed to bring .my improveclwemergenoy extension mechanism intoioperation. That, is to say, it is only necessary forithe pilottogive the releasing cable 2l a single jerk, when the spring [6- will'be brought into operation for-x-raisin -lthe cable 8- and extending. the undercarriage: It will be recognizedithatthis-is a particularlyimpo rtant hg t e undercarriage upon failureof the conven- 5 tional means of extension, said emergency extensionme'chanism including .a cylinder, a, source of energy in the cylinder, means operatively connecting the source ofenergy with the undercarriage a .release member on the cylinder and 0 's'hift'able for releasing the source of energy and extending the undercarriage, and-means connected with said last mentioned means and engageable by the pilot for shifting saidmember.

7,4 Innombination with a retractable rmderc'aniage, foraircraft, andconventional means completely operative .in itself for extending the undercarriage, a completely independent emergencyextension mechanism for quicklyQextending therundercarriageupon failure of theconventional. means of extension, said emergency extension mechanism including a cylinder, asource of energy in the. cylinder,- means operatively con- .necting the .source of energy with the undercarriage, a. release member on the cylinder and shiftablefor releasinglthesource of energy and extending the undercarriage, and -means connected with said last-mentioned .means and engageable by the pilot for shifting saidlmember, said last mentioned means comprising a releas- -his.- hip.'is.abouttoiland before letting-downsaid jng Gamer-connected with said release memberother meansof extension; The mechanismhereundercarriage, in the interest-ofispeed; When ORGE HERBERT DOWTY,

the pilotis about-to land his ship,he hasrmany duties to perform and, shouldzthe mechan'ism-ifor REFERENCES CITED extendingthe undercarriage;.nonnall :failtd p F The following references. are of record in the erate,:he'will have littletimetovgivetoloperating filemf -this patent:

inabovesdescribed 'requires norfurtherwattention U [EDWSTATES 'PAJENTS after theinitial 'pu'll has been given toztheire- N be me. Date leasingcable 2 L 1,922,371: Jones Aug. 15, 1933 Having thus described :the invention, whatiis 2,180,462 De Seversky .'Nov. 21, 1939 claimed as new is:

I V v r2,'001;620' Lev May 14, 1935 1. :In combinati0n witha retractable-aircraft FOREIGN-PATENTS undercarriage andconventional means completely operativein itself for extendin :theundercar- "35 Number D9309 fiage, acompletely independent emergency =ex- 460,316 GreatzBritain Jan. 26, 193'? tendingfimechanism including a releasable source 

